Abstract : Ten steady-state visual evoked responses (VERs) were recorded from each of 47 normal, adult subjects. For each subject, the mean and standard deviation for the ten VER amplitudes were calculated and used to determine amplitude variability. While some subjects produced extremely reliable VERs, data from the majority showed a considerable degree of variability. A number of factors including trend, noise, attention, binocularity, accommodation, eye movements, artifacts and electrode placement were evaluated to determine their relative contributions to this variability. Noise and trend factors produced a large proportion of the variability (62%) while the other factors were found to be relatively insignificant. (Author)